(201c) PCL-Gelatin Electrospun Fibers: Fabrication and Characterization

Popular biodegradable electrospinable polymers are polycaprolactone (PCL), gelatin (Gel). PCL is non-toxicity, biocompatible and biodegradable.  PCL synthetic polyester has gained much attention due to its low melting point (60 C^o) and elastomeric properties. PCL has been studied to form many medical devices, or scaffolds for tissue regeneration of in vivo and in vitro cell culture using serum added media.  To alter the hydrophobic characteristics of the surface, PCL has been blended with many natural polymers and also has been extensively evaluated in electrospinning process.  Gelatin natural polymer has been widely studied and exposed to various biomedical applications due to its excellent biocompatibility and biodegradability.  Blending natural and synthetic polymers provides a new biomaterial with proper biocompatibility and improved mechanical, physical and chemical properties which is beneficial for cell adhesion and degradation rate. In this study, we addressed the fabrication of biocompatible and biodegradable electrospun fibers by utilizing two different solvent systems to dilute the spinning solution for a possible increase in process productivity and fibers size. We also varied the PCL-Gelatin ratio in the spinning solution to evaluate the influence of PCL-Gelatin continent on the biological, mechanical properties and stability of the fabricated scaffolds and cellular behavior. We tested the ratio of PCL-Gelatin component under two different combinations 70:30 and 50:50 PCL-Gelatin respectively. Two different solvent system were tested Trifluoroethanol (TFE) and Hexafluoro-2-propanol (HFP) based on solution electrospinability and fiber uniformity. Distribution and stability of gelatin was studied in two-week incubation under physiological condition study using carboxyfluorescein diacetate-succinimidyl ester (CFDA-SE) staining and incubation. Fibers fabricated from PCL-Gelatin in HFP and TFE were compared and characterized for their size, structural and morphology using scanning electron microscopy and digital micrographs.  In addition to in situ analysis via fluorescence microscopy, differential scanning calorimetry (DSC) and FTIR were performed to characterize various components in the fabricated fibers.  Tensile tests (both wet and dry) were also measured to assess the uniform distribution of polymers.  24-h viability of human umbilical vein endothelial cells was also evaluated.  The hydrophilicity of electrospun fiber was also measured by contact angle. SEM images of electrospun fiber of PCL-Gelatin in TFE solvent system revealed that the fibers are slightly different in size, while fibers fabricated from PCL-Gelatin in HPE were more uniform in size, production process is significantly slow.  With the use of TFE, production rate significantly increased.  Combination of PCL-gelatin was stable for two-weeks at physiological conditions.  The  results also showed that gelatin distribution in PC-Gelatin fiber was uniform.  This provided improved cellular response due to distributed gelatin not only provides uniform cell binding domains to cells but also increases the fiber stability while cell culture study in aqueous media.